Couple quick facts about Pacific bluefin tuna, a fish that’s sold as sushi, mostly in Japan:
1. A 490-pound specimen caught off northeastern Japan sold during a fish market auction for ¥155 million. That’s nearly $US1.8 million. For a single fish. The winning bidder, Kiyoshi Kimura, president a sushi restaurant chain, broke the record for the highest price paid for a single bluefin tuna. Kimura set the previous record of ¥65 million one year earlier. Read all about it.
2. The Pacific bluefin population has plummeted 96.4 percent because of decades of overfishing, scientists reported in a recent stock assessment. Pew Environment Group’s Amanda Nickson warned that the species “is in danger of all but disappearing.”
So get your bluefin sushi on while you can. Or don’t.
The grand pine forests that dominate the Rocky Mountains in the American West morph with the montane altitudes. High peaks are home to whitebark pine, a slow growing species that produces energy-rich, pine cone-encased seeds that help grizzly bears grow plump enough to survive hibernation. At lower altitudes are the faster growing lodgepole pines.
The lodgepole pines have long been plagued by occasional infestations of native pine beetles. These dark beetles burrow into tree bark to lay their eggs, which hatch into larvae that feast on the phloem. (Phloem is a tender organ found just beneath the bark that ferries sugars produced by photosynthesizing leaves to other parts of the tree.)
A full blown infestation of phloem-munching beetle larvae is generally fatal. But lodgepole pines have developed a repertoire of defenses against the herbivorous creepy crawlies. They churn out sap and pour it over the invading beetles. They exhale chemicals that repel and kill the adults, prevent eggs from hatching and wreak general havoc with the beetles’ diminutive ecosystems.
Whitebark pines have not developed these defenses, at least not to the same extent as their lower-altitude cousins, because they haven’t needed them. The beetles can’t bear the bitter winters that have long swept over the Rocky Mountains’ higher peaks. But now, as climate change sweeps warmer weather over these towering peaks, the whitebarks are in newfound peril.
During occasional warm periods in the past, the beetles would march up the mountains and find a footing in whitebark forests. Then temperatures would return to normal and the pest populations would die off.
The warming peaks have ushered in an era of beetle infestations that many of the trees have been unable to withstand. More than 100 million acres of mountain forest has been impacted during the past decade. Great forests that used to soak up carbon now lay dead and rotting, releasing their carbon back into the atmosphere, further accelerating the global warming that contributed to their demise.
I asked the study’s lead researcher, Ken Raffa, an entomology professor at the University of Wisconsin, Madison, whether he thought the whitepines would be able to evolve defenses against the pine beetles quickly enough to protect themselves from being wiped out. He said he didn’t know: This is something he’s currently investigating, by studying how various tree genotypes are distributed across the mountain landscapes.
But of particular concern to Raffa is the fact that whitepines grow and reproduce very slowly, not producing viable seeds until they reach their 50s, while the beetles can reproduce every year or two, creating an evolutionary handicap.
In addition to marauding beetles, the whitepines also face tremendous threats from white pine blister rust, a ravaging fungus disease. “To be viable,” Raffa said, “whitebark pine would have to escape both.”
The fish live along the floor of the ocean off Southeastern Australia, leading generally lethargic lives and grabbing at passing sea urchins and mollusks. These deep-sea creatures share similar habitats with lobsters and crabs. They are often plucked from the ocean as by-catch by fishermen targeting the nearby crustaceans with their trawlers.
A flurry of news articles appeared a few years ago warning that the destructive trawling practices had left the blobfish in danger of extinction. Problem is, the fish is so rarely encountered by humans and it has been studied so little by scientists that nobody really knows how it’s faring.
“The assertion that the blobfish is threatened is the overlap of its small geographic range and habitat with the areas hit hard by deep sea bottom trawling,” said University of York Professor Callum Roberts, a marine conservation biologist whose research focuses on human impacts on marine ecosystems, “and the fact that it seems to be rare.”
The last great extinctions occurred 65 million years ago, when land-dwelling dinosaurs disappeared and mammals began an ascent that eventually led to our own evolution. The dinosaurs were doomed when the Earth clouded over with smoke. The darkened world grew cold, reptiles were unable to bask effectively and plants struggled to photosynthesize. While other kingdoms of life flailed, fossil records indicate that fungi flourished.
Fungi are the world’s great decomposers, and during periods of environmental upheaval they can become savagely pathogenic, feasting on the living flesh of the weak. But fungus does not grow well in hot conditions. In 2005, Arturo Casadevall suggested that the rise of fungus during the Cretaceous–Paleogene extinction event selectively killed off cold-blooded dinosaurs and gave warm-blooded mammals the opportunity to prosper. In August, the Albert Einstein College of Medicine professor published a followup paper in PLOS Pathogens that expanded and built upon his theory.
“Primitive mammals like the platypus, with core temperatures near 32°C, are susceptible to Mucor amphibiorum, a fungus with a maximal thermal tolerance of 36°C that would make it avirulent for higher mammals. The resistance of mammals to fungal diseases is in sharp contrast to the vulnerability of other vertebrates, such as amphibians, a group that is currently under severe pressure from a chrytrid. Like mammals, amphibians have adaptive immunity, but unlike mammals, they are ectotherms and lack a thermal environment that is exclusionary to fungi.”
Casadevall tells me he’s more confident now in his theory than he was when he first described it seven years ago. That’s partly because of a study that he co-authored in 2010 that indicated that the human body temperature is almost ideally optimized for warding off fungal diseases while maintaining metabolic needs. He said the spread of white nose syndrome, a soil fungus that in North America has killed millions of hibernating bats, whose temperatures plummet during winter, provides additional support for his theory.
“People have been intrigued with the fungal-mammalian hypothesis,” Casadevall told me. “There has been no significant pushback.”
In his new essay, Casadevall says global warming could help fungi adapt to warmer temperatures, potentially reaching a point where pathogenic species could develop newfound abilities to infect warm-blooded mammals. Such a development could be disastrous for humanity, as I explain in Slate.
[To join a LinkedIn group devoted to the discussion of fungus diseases, click here.]
Nigerian oil spill officials have accused an Exxon Mobil subsidiary of using harmful oil dispersants at the site of a large spill without their permission.
BP used similar dispersants after the Deepwater Horizon spill, sickening cleanup workers. The toxic chemicals help oil blend with water. That removes some slick from the surface; a public relations exercise that hides spilled oil and disguises the true size of a spill. But it plunges the spilled fuel deep into the water column, where it’s deadly to fish, dolphins, plankton and other marine life.
As Mobil Producing Nigeria seeks to contain its third oil spill in just three months at the Qua Iboe oil fields, along the Atlantic coastline, the company has angered National Oil Spills Detection and Response Agency officials through its use of dispersants.
The company is telling the press that it received permission to use the dispersants from the Department of Petroleum Resources. Not only does Idris say that’s irrelevant – he insists that his agency is in charge of oil spill responses – but he appears to question the very honesty of Mobil’s claim.
“The DPR approval letter is questionable and we should see it,” Idris said.
The problem is vast and widespread. The U.S. Fish & Wildlife Service estimates that 100 million to 1 billion birds are killed by flying into buildings every year in the United States alone. (By comparison, the same agency estimates that cats kill 40 million birds yearly in the U.S. and that nearly 200 million are killed by electrocution.)
In response, some cities, such as San Francisco, require developers to protect birds by making their windows easier to see with avian eyes. This can be done by etching or frosting the glass, painting the windows with UV patterns that are more easily spotted by birds or by building architectural features across them.
Similar laws apply in Toronto, home to Menkes Developments’ Consilium Place, which was at the heart of the recent case. But the laws there only apply to new construction.
The outcome was not a total loss for bird populations or bird lovers. In response to the lawsuit, the office complex in 2011 was coated with film in a successful bid to reduce the number of birds that unwittingly fly into it.
“The number of collisions is dramatically down,” Ecojustice lawyer Albert Koehl told The Star newspaper, “so there are obviously solutions that do work.”
The Australian island state of Tasmania is home to two famous species of marsupial, both of them carnivorous dog-like creatures. The striped Tasmanian tiger went extinct in the 1930s. And now the Tasmanian devil, a stockier creature with mostly solid black fur, is staring down a similar fate.
The species is dying from a face cancer that kills swiftly and spreads from one devil to another when the creatures bite during fights. More than 90 percent of the wild population has been killed since scientists first noticed the contagious tumors in the mid-’90s.
In a desperate bid to save the species, Australian officials are embarking upon a radical experiment: Some of the few remaining healthy specimens, bred in captivity, will be introduced into an environment where they will become an invasive species.
The 14 healthy devils will be released Thursday on Maria Island, a tiny island off Tasmania’s eastern coast that is wholly comprised of national parkland. More than 100 of the animals could eventually be released there.
“The Maria Island translocation is designed to establish a self-sustaining population of healthy wild devils in a safe haven where they are protected from interaction with the deadly facial tumour disease,” Tasmania’s environment minister, Brian Wightman, told the AFP.
Although the devils can swim, they have never before reached the 22,000 acre island. When they get there, they will feast on penguins, geese and other native animals that are unaccustomed to their vicious presence. They will compete with wedge-tailed eagles for prey; they could help an invasive population of rats flourish by killing off the invasive population of feral cats; and they might damage World Heritage–listed buildings by burrowing under them.
That said, most of the Australian conservation movement and political establishment appears to support of the project, with the widespread caveat that it is done carefully and with extensive monitoring.
The risk of the devils going the way of the dodo is too much for most Australians to bear.
“Translocation is one of the methods of last resort,” Australia’s environment minister, Tony Burke, a supporter of the project, told Fairfax Media. “It has to be done carefully, with good scientific oversight.”
Large, old trees sporting gaping holes in their trunks are like empty nesters who open their homes and hearts to foster kids, or to help raise grandchildren.
Tree cavities provide homes for all manner of life, including mushrooms, birds, bats and possums. They can provide respite from squalls and from scorching or freezing temperatures, sculpting microenvironments and boosting biodiversity.
But these holes are disappearing.
Tree holes normally arise over painstakingly long periods, sometimes with the assistance of woodpeckers, termites or fungus. They are most commonly found in the most senior members of a tree stand. Sometimes, cavity-pocked trees are dead trees that remain standing for decades.
Scientists warn that climate change, logging and other human activities are prematurely felling the world’s oldest trees, taking their cavities down with them. Droughts and intense fires are taking heavy tolls.
“Many ecosystems worldwide are increasingly characterized by the rapid loss of large trees with cavities, a failure to recruit new trees with cavities, or both,” the scientists wrote. “Many kinds of human disturbances cause this problem, including recurrent logging, altered fire regimes, grazing by domestic livestock, and the impacts of exotic plants.”
The scientists monitored populations of Eucalytpus trees in the southeastern Australian state of Victoria, some of which were growing in areas hit hard during unprecedented bushfires in 2009 that killed 173 people. They found an alarming decline in the number of cavity-bearing specimens.
In areas severely impacted by fires, the number of cavity-bearing trees declined from 138 in 2006 to 42 in 2012, greatly diminishing the number of holes available for use by Leadbeater’s possums and other creatures. But the losses were also staggering in areas unaffected by fire: The number of cavity-bearing trees in these areas fell from 414 in 1997 to 159 in 2011.
“There was a heat-induced, drought-induced mortality spike in the deaths of large trees,” lead researcher David Lindenmayer of the Australian National University told me in an email. “These kinds of findings are seen in many kinds of forests worldwide.”
Perhaps even more alarmingly, during this period of disappearing holes, not a single new tree cavity was formed in the study area during the entire 15 years of research. It’s as if hundreds of homes were razed but no new ones were built to replace them.
Forests suck carbon dioxide out of the air. They use solar energy to combine the carbon dioxide with water droplets to form sugars that fuel plant growth. During that chemical reaction, known as photosynthesis, waste oxygen is released back into the air.
So the effects of widespread deforestation by lumberjacks and bulldozers are relatively easy to understand. Less forests means more carbon dioxide, which heats the planet, and less oxygen for us to breathe.
New research has revealed that deforestation can take an even more sinister turn when it’s performed by a fungus. Fungal pathogens and fungus-like diseases are stealthily felling forests across the world. Forests at Big Sur disappeared in less than a decade after sudden oak death moved onto their turf. Cypress canker, native to California, is destroying trees across Europe. Dutch elm disease has forever changed the landscape on the East Coast.
These symptoms of a sick planet do more than merely strip the earth of some of its greatest carbon sponges. Scientists have discovered that fungus disease can cause some of the wood in infected trees to break down not into carbon dioxide (CO2), but to break down anaerobically with the assistance of bacteria into methane (CH4), which is a far more potent and damaging greenhouse gas.
The university researchers measured methane levels in Connecticut woodlands infected by heart rot, a fungus disease, and reported in the journal Geophysical Research Letters that concentrations were so high in some places that it was flammable. Methane concentration in the air is normally less than 2 parts per million, but the researchers discovered levels in some trees that reached more than 160,000 parts per million. The average methane concentration in the forest was 15,000 parts per million.
The ailing forest was releasing enough methane to counteract the climate-cooling benefits of nearly one-fifth of the carbon dioxide it was absorbing, researchers calculated.
The researchers point out that their study covered just one forest, and one type of fungus disease. This particular disease is unique in that the trees often appear outwardly healthy while they rot away from the inside. But they warn that other fungal diseases that are laying waste to woodlands around the world could have similar effects.
“I think it’s fair to say that wood-rotting fungi in general could lead to this effect,” lead researcher Kristofer Covey, a Ph.D. candidate at Yale University’s School of Forestry, told me. “It’s hard to say if more aggressive fungal pathogens could lead to further emissions or not.”
Now is a terrible time to be losing forests. They are needed to help soak up all the carbon we’re pumping into the atmosphere when we burn fossil fuels. So this discovery comes as a double-whammy: Not only are we losing carbon-storing forests to fungus, but the fungi are taking carbon that had been stored in the trees and helping to turn it into a particularly potent greenhouse gas that further accelerates the rate of climate change.
The discovery offers one more reason to protect our forests from fungus diseases. Unfortunately, the problem has become so rampant that there is very little that we can do about it.
Scientists had never encountered anything like it.
Discovered in the late 1990s by researchers trying to figure out why frog populations were disappearing around the world, Batrachochytrium dendrobatidis, or B.d., has already wiped out perhaps 200 to 300 amphibian species. It has shaken ecosystems, starving birds and other frog eaters and allowing insects to run rampant.
“We have something the world has never seen before,” Vance Vredenburg, a biology professor at San Francisco State University who specializes in amphibians, told me earlier this year. “It’s jumping from species to species to species.”
The recent discovery that chytrid was present in New England in the 1960s, three decades before the disease’s effects were noticed, points to the alarming possibility that the die-offs are the result of worldwide environmental degradation.
B.d. is a type of chytrid — a member of the most primitive division of fungus: Chytridiomycota. Toadstools, molds and all of the other forms of fungus evolved from chytridiomycotes. Chytridiomycotes today are the smallest and simplest type of fungus, but these wily grandfathers still pack one helluva punch.
Before a frog is infected, it is hunted down by swarms of tiny chytrid zoopores that propel themselves through the water by flapping their tail-like flagella. The pathogen changes shape and burrows into the frog’s skin, which it consumes while it creates more zoospores, causing the frog to grow more layers. Many species can tolerate the parasites at low doses, but once a frog’s skin is infected with enough of the fungus it will go into cardiac arrest, its electrolyte levels thrown out of balance and its tiny heart stopped. (Weirdly, some species, including the American bullfrog, appear completely immune.)
“We find literally hundreds, and tens of thousands — I’ve seen it myself — dead animals on the shorelines of lakes,” Vredenburg said.
Kathryn Richards-Hrdlicka, a doctoral candidate at the Yale School of Forestry and Environmental Studies, took samples from 10 species of amphibians preserved in formalin at the Peabody Museum of Natural History. She reported Tuesday in the journal Methods in Ecology and Evolution that the fungus was infecting frogs in New England as long ago as 1968, the year in which one of the oldest of the studied specimens was collected.
“It’s possible dieoffs did happen back then and no one noticed, although die-hard herpetologists around here tell me someone would have noticed,” Richards-Hrdlicka told me. “I think it’s possible that when B.d. came to New England, it may have wiped out the more susceptible lineages or gene pools and what we’re left with today are those gene-pool winners. That may explain why I can pick up 10 frogs here and three to four of them will be infected, with light zoospore loads, and show no signs of infection.”
Alternatively, rampant world trade could have brought two chytrid strains into contact that merged to spawn a super pathogen, as other B.d. researchers have hypothesized.
But Richards-Hrdlicka also said that the changing environmental conditions facing all species around the world right now might simply make frogs more vulnerable to the chytrid than they were in the past.
And there’s the rub. When frogs were disappearing without explanation in the 1990s, many speculated that the chordata class amphibia was acting like a canary in a coal mine, dying off before other types of animals because they are so sensitive to their environment.
The discovery of B.d. muted that suspicion, but now we know that B.d. was present long before these prominent collapses. Previous studies showed it was lurking in Africa in the 1930s.
Fungus is the great decomposer. When animals and plants are stressed, their defenses weaken and they can be eaten alive by fungus, which treats its prey as though it is dead flesh awaiting decomposition. So perhaps the mystery of the disappearing frogs really can be traced back to just about everything that is out of whack with our environment: Climate change, pesticides, habitat loss, water diversions, water degradation, air pollution, you name it.
Scientists had never encountered anything like B.d.
That’s when bats in a cave in New York started dropping dead from white nose syndrome. Since then, the disease, which is caused by a type of soil fungus that chews through the mammals’ wings, has spread rapidly west, killing an estimated 7 million hibernating bats in just six years.
“That’s really similar,” Vredenburg said.
This illustrated ecology blog is no longer updated.